I noticed others have suggested online play, with up to 30 individuals playing at the same time. That might be the best way to play against a decent defence, depending out what EA Sports come up with of course.
Might not be that fun playing a prop though (no offence to props) so maybe a single person could play any number of the players from one team at the same time, toggling between players as you do in the current game. E.g 3 players on the same side might have 5 players each, probably distruting 10, 12 and 13 between them to ensure they each get a player who gets a lot of ball.
Even if playing with 30 players it would be good to be able to remove the "focus" from your player in order to get guidance from the computer as to where you should be standing.
That would create a platform for online tournaments, prizes, etc...
Would also give the ability to add complexity to the scrum, rucks etc...